1. Technical Field
The present invention relates to an optical touch system, and more particularly, to a method of detecting a gesture and an optical system using the same.
2. Related Art
In an optical touch screen system, the method of calculating the position of an object is to use an image sensor to generate a picture, analyze the location of an object image in the picture, and calculate the coordinates of the object by the location of the object image in the picture and a portion of geometric dimensions of the optical touch screen system.
U.S. Pat. No. 4,782,328 discloses an optical touch screen system, which comprises two image sensors and a processor coupled with the two image sensors. The two image sensors are configured to capture the image of an object on a touch screen. The processor is configured to decide sensing paths respectively connecting the object and the two image sensors, and further to calculate the coordinates of the object using the sensing paths.
U.S. Pat. No. 7,689,381 B2 discloses another optical touch screen system, which comprises a mirror, an image sensor, and a processor. The mirror is disposed at the periphery of a touch area. The mirror generates a reflection of an object. The image sensor captures an image of the object and an image of the reflection. The processor determines a sensing path passing through the image of the object and a sensing path passing through the image of the reflection, and determines the coordinates of the object by using the two sensing paths.
Multi-touch technology can simultaneously recognize the presence of two or more objects on a touch surface. This plural-point awareness is often used to implement advanced functionality such as a pinch to zoom or activating predefined programs.
Current optical touch systems use the multi-touch technology to calculate the coordinates of plural objects at each predetermined time and send the coordinates of the objects calculated at different times to multi-touch applications. Multi-touch applications are designed with predefined gestures. Common gestures may include a pan gesture that uses a single finger or multiple fingers to perform scrolling, rotate, and zoom gestures. In addition, a single finger gesture such as a press and tap, flick, press, and drag gesture is also used frequently. Moreover, another common gesture is a double-tap gesture, which can be customized by specific software to perform a particular function: for example, to start a game.
Multi-touch applications can adopt an event driven model as their basic conceptual designs. After a computing system captures a touch event, a registered event handler is called to implement a desired functionality.
During multi-touch operations, current optical touch systems supporting a multi-touch have to calculate coordinates of multiple objects at different time points and to output the coordinates of the objects to the multi-touch applications. The calculation and output of the coordinates of the objects take much time and consume a lot of resources, resulting in slow response of the optical touch systems.